It is known an information recording medium cartridge as shown, for example, in FIG. 42.
The information recording medium cartridge (refer hereafter to as “cartridge” simply) 101 is provided with an information recording medium (refer hereafter to as “disc”) 102, such as optical disc, magneto-optical disc or the like, having recording layers arranged on right and reverse sides, a cartridge casing (refer hereafter to as “shell”) 103 which rotatably stores the disc 102, and a shutter 105 slidably mounted to the shell 103 for opening and dosing recording and/or reproducing openings (refer hereafter to as “openings” simply) arranged in right and reverse sides of the shell 103.
The shutter 105 is provided with a first shutter plate 106 which opens and closes an opening 104 on the right side of the shell 103 and a second shutter plate 107 which opens and closes the opening 104 on the reverse side of the shell 103. The shutter 105 is formed roughly like an U shape by bending a metal plate to simultaneously open and close the openings 104 on the right and reverse sides of the shell 103.
When loading the cartridge 101 into a recording and/or reproducing device (refer hereafter to as “drive unit”), the shutter 105 is driven and operated by a shutter operating member mounted to the drive unit to simultaneously open the openings 104 on the right and reverse sides of the shell 103.
With the cartridge 101, as shown in FIG. 43, the disc 102 is chucked on a turntable 301 of the drive unit through the opening 104 on the reverse side of the shell 103 for rotation and driving, and recording and/or reproducing of the disc 102 is carried out by an optical pickup 302 through the opening 104 on the reverse side.
With the conventional disc 101 using the shutter 105 having first and second shutter plates 106, 107 integrally formed, when opening the opening 104 on the reverse side of the shell 103 for recording and/or reproducing, the opening 104 on the reverse side of the shell 103 is also opened even when there is no direct relation directly with recording and/or reproducing, raising an inconvenience that dust 303 or the like entering the shell 103 through the opening 104 on the right side adheres and deposits on the top surface of the disc 102. Adhesion of the dust or the like has a considerable adverse influence on a high-density large-capacity disc.
In order to solve the above inconvenience, a cartridge 201 using a divided shutter as shown in FIGS. 44–45 has been developed. In the cartridge 201, a shutter 205 comprises a first shutter plate 206 which opens and closes an opening 204 on the right side of a shell 203 and a second shutter plate 207 which opens and closes an opening 204 on the reverse side of the shell 203. The first and second shutter plates 206, 207 are moved individually to open and close the openings 204 independently.
The first and second shutter plates 206, 207 are provided with a closing portion 208 which doses the opening 204 and an open portion (recessed window) 209 continuously arranged with one side of the closing portion 208 to open the opening 204.
As shown in FIG. 44, when the first and second shutter plates 206, 207 are in a first position, the closing portions 208 of the first and second shutter plates 206, 207 are in the overlapped state to dose the openings 204 arranged in right and reverse sides of the shell 203. And when being moved to a second position as shown in FIG. 45, the open portion (recessed window) 209 and the openings 204 are overlapped one another, opening the openings 204.
As shown in FIG. 44, the first and second shutter plates 206, 207 are mounted to a slide member 210. The slide member 210 is divided into a first slide portion 211 to which the first shutter plate 206 is mounted and a second slide portion 212 to which the second shutter plate 207 is mounted. The first and second slide portions 211, 212 are formed by vertically dividing the slide member 210 into two parts in the moving direction.
When loading the cartridge 201 using the divided shutter into the conventional drive unit (second drive unit) for a divided-shutter type cartridge, one of the first and second shutter plates 206, 207 is driven and operated by a shutter opening member 404 mounted to the drive unit 203 as shown in FIGS. 44–45 to open only the opening 204 on the reverse side of the shell 203. And as shown in FIG. 46, through the opening 204 on the reverse side of the shell 203, the disc 202 is chucked on a turntable 401 of the drive unit for rotation and driving, and recording and/or reproducing of the disc 202 is carried out by an optical pickup 402. On the other hand, the first shutter plate 206 closes the opening 204 on the right side of the shell 203 to prevent an intrusion of dust 303 or the like into the shell 203 through the opening 204.
The conventional cartridge 201 using divided shutter raised the following problems:
1) Since it is constructed that the first and second shutter plates 206, 207 are fixed to the first and second slide portions 211, 212 by screws 225, the mounting workability of the first and second shutter plates 206, 207 to the first and second slide portions 211, 212 is unfavorable. Moreover, when the screws 225 loosen and drop out, the first and second shutter plates 206, 207 also drop out easily from the first and second slide portions 211, 212.
2) With the conventional cartridge 201 using divided shutter as well, it is difficult to surely prevent an intrusion of dust 303 or the like into the shell 203 through the openings 204. The reason is as follows. Sure prevention of an intrusion of dust 303 or the like into the shell 203 through the openings 204 requires close contact of the first and second shutter plates 206, 207 with shutter slide faces 203a of the shell 203 in the first portion. However, when trying to slide the first and second shutter plates 206, 207 in the direction to open the openings 204 while being in close contact with the shutter slide faces 203a of the shell 203, friction produced between the first and second shutter plates 206, 207 and the shutter slide faces 203a of the shell 203 can inhibit smooth sliding of the first and second shutter plates 206, 207 or bring the shutter slide face 203a of the shell 203 to be cut by the first and second shutter plates 206, 207 to produce wearing powder, which is adhered on the disc 202, causing so-called dropouts such as skip.
3) The shutter-opening-member engagements 213 are formed by punching the first and second shutter plates 206, 207, so that when a shutter engaging pin 405 of a shutter opening member 404 of the second drive unit is engaged with the shutter-opening-member engagement 213, the shutter engaging pin 405 is cut by the edge of the shutter-opening-member engagement 213. Moreover, the inner peripheral surface of the shutter-opening-member engagement 213 is deformed by the pressure applied on the shutter through the shutter engaging pin 405.
4) When the recording and/or reproducing method of the disc 202 of the conventional divided-shutter type cartridge 201 is different from that for the disc 202 of the divided-shutter type cartridge 201 of the present invention, and when a cartridge casing of the conventional divided-shutter type cartridge 201 is formed in substantially the same size and shape as that of the divided-shutter type cartridge of the present invention, the divided-shutter type cartridge of the present invention can be inserted by mistake into the drive unit for the conventional divided-shutter type cartridge. If the divided-shutter type cartridge of the present invention is inserted by mistake into the drive unit for the conventional divided-shutter type cartridge, the disc of the divided-shutter type cartridge of the present invention can be damaged from the drive unit for the conventional divided-shutter type cartridge, because their recording and/or reproducing methods are different.
An object of the present invention is to solve the conventional problem 1), and to provide an information recording medium cartridge which allows sure and easy mounting of a shutter plate to a slide portion without using screws or the like which are needed in the prior art.
Further, another object of the present invention is to solve the conventional problem 2), and to provide a cartridge which allows smooth sliding of a divided shutter and close contact of the first and second shutter plates with the shutter slide faces of a shell in the first position (position of closing the openings).
Furthermore, still another object of the present invention is to solve the conventional problem 3), and to prevent a shutter engaging pin of a shutter opening member of a drive unit from being damaged by a shutter-opening-member engagement as well as to prevent the shutter-opening-member engagement from being subjected to the deformation or the like.
Moreover, a further object of the present invention is to solve the conventional problem 4), and to prevent a divided-shutter type cartridge of the present invention from being loaded by mistake into the drive unit for the conventional divided-shutter type cartridge which is different in the recording and/or reproducing method.